"In 1937 Knox cracked the code of the commercial Enigma machines used by Franco's Nationalists in the Spanish Civil War"
Read here of Alfred Dillwyn "Dilly" Knox.
Another one of those eccentric but very talented persons the English are so fond of. Contributed in a significant manner to German defeat in both World Wars.
"Alfred Dillwyn 'Dilly' Knox . . . was a classics scholar at King's College, Cambridge, and a British codebreaker [cryptanalyst]. He was a member of the World War I Room 40 codebreaking unit, and later at Bletchley Park he worked on the cryptanalysis of Enigma ciphers until his death in 1943."
It should be noted that Knox was NOT a mathematician. WAS a classics scholar. NOTED for his linguistics abilities - - able to speak Greek, Latin, etc., in the ancient and modern forms. Knowledgeable in the works of the ancients, etc.
To defeat the commercial version of the Enigma cryptographic machine, Knox and his colleagues devised a LINGUISTIC approach to the matter, as opposed to the mathematical solution as applied to the military version of the same machine. The German military version of the Enigma possessing the plug board [stecker]
The technique as used by Knox was referred to as "rodding". Read at the link below an entire description of "rodding". Too complicated for me to follow.
" 'RODDING' - - This technique . . . was used to break messages that had been enciphered on Enigma machines that did not have a plug board."
Read further about "Dilly" Knox and the role of "Classics and Intelligence" here.
Students and scholars of the "classics" indeed have strong minds that are highly trained and are able to unravel puzzles such as was posed by Enigma. "Dilly" Knox is the archetype in this regard?